There has been a demand for magnetic material having a high coercive force as well as high mechanical hardness for use, especially as a film for magnetic recording media. The material must be hard to resist impacts from a flying magnetic head slider and be resistant to corrosion. A thin film of a magnetic material is needed in order to increase the density of magnetic transitions formed on the magnetic material by the magnetic transducer. Particulate magnetic recording media are limited in density by the size of the magnetic materials and the binder which limits the lower level of thickness which can be accomplished.
Magnetic recording media comprise important memory units in electronic computers, especially for magnetic memory discs. An object of the present invention, therefore, is to provide a new magnetic material useful as magnetic recording media.
It is known that conventional particulate ferromagnetic materials such as iron oxide and chromium dioxide can be dispersed into an organic binder to form a coating layer type of magnetic recording medium. However, ferromagnetic metallic thin films produced by vacuum or vapor deposition have attracted special interest because of the relative thinness of the resultant magnetic layer.
Electroless plated thin films of cobalt or nickel are well known as evidenced by the many issued patents in this area.
Iron rhodium has been suggested as magnetic recording media as exemplified by U.S. Pat. No. 3,607,460 to J. M. Lommell. This patent suggests depositing iron and rhodium as separate layers and then annealing to defuse the layers.
Further thin film magnetic recording medium comprises a magnetite film prepared by forming a film of Fe.sub.2 O.sub.3 as disclosed in U.S. Pat. No. 3,620,841 to R. L. Comstock et al and assigned to the assignee of the present application.
In many of the patents, the magnetic film is formed on the substrate by conventional electroplating or evaporation plating such as vapor deposition, sputtering, or ion plating. The magnetic film is made of metal generally, for example, ferromagnetic metals such as iron, cobalt, nickel, and the like or ferromagnetic alloys including a combination of the ferromagnetic metals with the addition of certain materials for specific purposes. For instance, platinum and rhodium have been included with the ferromagnetic materials to accomplish a magnetic recording media.
Also, as suggested in U.S. Pat. No. 4,002,546, magnetic recording media of a cobalt silicon alloy can be ion plated.
It is further known that amorphous alloys can be formed having magnetic properties. For instance, the article, appearing in the Journal of Applied Physics, Volume 47, No. 10, October 1976 at pages 4660-2 entitled "Low-Field Magnetic Properties of Fe.sub.80 B.sub.20 Glass" by R. C. O'Handley et al, discusses the magnetic properties of metallic glasses. These magnetic glasses have extremely low coercivity which renders them unsuitable for magnetic recording media. Similar amorphous transition metal alloys such as iron carbon, iron phosphorous, and so forth are all very soft magnetic materials. The only examples of a high coercivity amorphous alloy involve ferromagnetic amorphous, rare earth-transition metal alloys near the compensation temperature or similar rare earth-transition metal alloys containing highly anisotropic atoms such as terbium.
Accordingly, an object of the present invention is to provide an amorphous magnetic material that has high coercivity.
A further object of the present invention is to provide a new amorphous magnetic material having properties rendering it useful as a magnetic recording media. In addition, an object of the present invention is to provide an enchanced magnetic material having relatively high coercivity along with good corrosion resistance. It is a further object of the present invention to provide thin films which are mechanically strong and are relatively resistant to wear.